1. Field of the Invention
Methods for detecting a cancer, such as ovarian cancer, are disclosed herein. Also discussed herein are methods for monitoring a cancer, such as ovarian cancer. More particularly, disclosed herein are methods for detecting ovarian cancer in a test subject by determining the amount of a lysophosphatidyl ethanolamine (“LPE”) in a sample of a bodily fluid taken from the test subject. The methods discussed herein are particularly useful as a screening test for ovarian cancer.
2. Background Information
Ovarian cancer is one of the deadliest cancers for women, due to its high fatality rate. In the United States in 2007, it was estimated that 22,430 women would be diagnosed with ovarian cancer and 15,280 women would die of ovarian cancer. Unfortunately, heretofore, only 25% of ovarian cancer patients were diagnosed at stage I. Most of the patients were diagnosed at an advanced stage, stage III or IV, at which the 5-year survival rate decreases to 20 to 25% from 95% at stage I.
Presently, the most commonly used biomarker for diagnosing ovarian cancer is CA-125, a group of surface glycoproteins with uncertain biological function. Although CA-125 is elevated in 82% of women with advanced ovarian cancer, it has very limited clinical application for the detection of early stage disease, exhibiting a positive predictive value of less than 10%. The addition of physical examination by diagnostic ultrasound improves the positive predictive value to 20%, which is still too low to meet the requirement for cancer detection. Developing a clinical test to diagnose ovarian cancer with high sensitivity and specificity at the early stage has become the most urgent issue in battling this refractory disease.
Frequently, the detection of cancer depends upon the detection and inspection of a tumor mass, which has reached sufficient size to be detected by physical examination. The detection of molecular markers of carcinogenesis and tumor growth can solve many of the problems associated with the physical examination of tumors. Samples taken from the patient for screening by molecular techniques are typically blood or urine, and thus require minimally invasive techniques. Thus, they can be used on a regular basis to screen for cancers. In addition, because molecular markers may appear before the tumor reaches a detectable size; it is possible to detect cancers at very early stages in the progression of the disease.
Biomarkers identified from serum proteomic analysis for the detection of ovarian cancer are discussed in Z. Zhang et al., Cancer Research, 64, 5882-5890, Aug. 15, 2004.
Methods for detecting a cancer associated with elevated concentrations of lysophospholipids have been described in US 2002/0123084 and US 2002/0150955.
U.S. Pat. No. 6,500,633 discloses a method of detecting carcinomas by measuring the level of a glycerol compound, such as glycerol-3-phosphate, in a plasma, serum or urine specimen from a patient.
US 2007/0196875 (inventors: Lian Shan and Stanley L. Hazen) discloses a method for detecting ovarian cancer using plasmenyl-PA as a marker.
US 2008/0020472 (inventors: Lian Shan and Lorelei D. Davis) discloses a method for detecting ovarian cancer using plasmenyl-PE as a marker.